Tunable wicking structures and a system for a wicking structure

ABSTRACT

Various systems and methods are provided for creating a wicking structure. In one example, a method for creating a wicking structure can include creating, using a 3D printing technique, a macro wicking element including a lattice structure formed by a grid of a first material, the lattice structure including pores formed between the grid of first material. The method can also include creating, using the 3D printing technique, a first micro wicking element including powder particles distributed within the pores of the lattice structure, and creating, using the 3D printing technique, a second micro wicking element by removing at least a portion of the lattice structure.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present matter is a continuation of and claims priority to U.S.patent application Ser. No. 16/228,281, filed Dec. 20, 2018, and titled“TUNABLE WICKING STRUCTURES AND A SYSTEM FOR A WICKING STRUCTURE,” thecontents of which are hereby incorporated herein by reference.

FIELD

Embodiments of the subject matter disclosed herein relate to methods andsystems for a tunable wicking structure.

BACKGROUND

Wicking structures may be used in a variety of applications in order tocontrol and/or direct a flow of fluid (e.g., via capillary action). Forexample, wicking structures may be used in candles/lamps (to draw liquidfuel for maintaining a flame), air fresheners (to draw scented oil to ascent distribution area), vaporization devices such as those used foradministering anesthesia (to draw liquids to a vaporization surface),air/liquid separators (to draw and direct liquid away from an air/liquidmix), and/or other applications. The capillary action in wickingstructures occurs due to the presence of hollow structures (e.g., tubes,pores, cells, etc.) in a wick. Adhesion between a liquid and an innerwall of a hollow structure pulls the liquid up the hollow structure, andthus up the wicking structure.

BRIEF DESCRIPTION

In one embodiment, a tunable wicking structure comprises a macro wickingelement including a lattice structure formed by a grid of solidmaterial, the lattice structure including pores formed between the solidmaterial, and a micro wicking element including powder particlesdistributed within the pores of the lattice structure.

In another embodiment, a tunable wicking structure comprises a microwicking element comprising a plurality of powder particles, each powderparticle of the micro wicking element being partially joined to at leastone other powder particle of the micro wicking element, and wherein aplurality of channels are formed between partially joined powderparticles of the micro wicking element for drawing liquid through themicro wicking element via capillary action.

In another embodiment, a system comprises a liquid reservoir for avaporizer of an anesthesia machine, a heating element coupled to aregion of the liquid reservoir, and a tunable wick disposed in theregion of the liquid reservoir, the wick comprising a micro wickingelement including a plurality of powder particles, each powder particleof the micro wicking element being partially joined to at least oneother powder particle of the micro wicking element to form a pluralityof channels for drawing liquid from the liquid reservoir through themicro wicking element toward the heating element via capillary action,the plurality of channels having a continuously variable size along adimension of the micro wicking element.

It should be understood that the brief description above is provided tointroduce in simplified form a selection of concepts that are furtherdescribed in the detailed description. It is not meant to identify keyor essential features of the claimed subject matter, the scope of whichis defined uniquely by the claims that follow the detailed description.Furthermore, the claimed subject matter is not limited toimplementations that solve any disadvantages noted above or in any partof this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood from reading thefollowing description of non-limiting embodiments, with reference to theattached drawings, wherein below:

FIG. 1 schematically shows an exemplary embodiment of a patient gasdelivery system including a tunable wicking structure.

FIG. 2 shows an exemplary embodiment of a tunable wicking structure.

FIG. 3 shows an exemplary embodiment of a tunable wicking structureincluding an encapsulating structure.

FIGS. 4 and 5 show cross-sectional views of exemplary embodiments oftunable wicking structures having different configurations.

FIGS. 6A-6C show detailed views of an exemplary embodiment of a tunablewicking structure including a lattice at 100× magnification, 250×magnification and 1000× magnification respectively.

FIGS. 7A-7C show detailed views of an exemplary embodiment of a tunablewicking structure including loose powder particles without a latticestructure at 100× magnification, 250× magnification, and 1000×magnification respectively.

FIG. 8 schematically shows an exemplary embodiment of a heat pipeincluding a tunable wicking structure.

FIG. 9 schematically shows an exemplary embodiment of an air/liquidseparator including a tunable wicking structure.

FIG. 10 shows an exemplary embodiment of a method for manufacturing atunable wicking structure.

DETAILED DESCRIPTION

The following description relates to various embodiments of a tunablewicking structure, such as the tunable wicking structure shown in FIGS.1-9 . The tunable wicking structure may be included in a variety ofenvironments, including the patient gas delivery system of FIG. 1 , theheat pipe of FIG. 8 , and the air/liquid separator of FIG. 9 . Anexample of a tunable wicking structure is depicted in FIG. 2 , showingcomponents of the tunable wicking structure including a lattice macrostructure and powder particles forming a micro structure within pores ofthe lattice. An example of a tunable wicking structure that includes anencapsulation structure is depicted in FIG. 3 . Examples of differentconfigurations that may be used to form a tunable wicking structure aredepicted in FIGS. 4 and 5 . FIGS. 6 and 7 show detail, microscopic viewsof powder particle arrangements within a tunable wicking structure. Anexample of a method for fabricating a tunable wicking structure is shownin FIG. 10 , the method including use of additive manufacturing togenerate components of the tunable wicking structure.

The tunable wicking structures described herein utilize sintered powderwithin a larger structure (which may optionally be removed to form afinal wicking structure product) to provide wicking capability throughcapillary action. In this way, the tunable wicking structures may have a“two-phase” structure, including solid and semi-solid powder (e.g.,produced using additive manufacturing). The use of sintered powderallows the tunable wicking structures to be integrated into other partsand tuned to a given application of the tunable wicking structure. Thetunable wicking structures can be tuned to include different pore sizeswithin a lattice structure and/or have variable geometry, unlike otherwicks, which may be limited to basic shapes and have a single pore size.

For example, the tunable wicking structures may include tunable macrostructures having various lattice size, shape, and/or orientation,through which part strength, thermal properties, mass, density, dampingcharacteristics, and/or other parameters of the wicking structure may beconfigured for an associated usage environment of the tunable wickingstructures. The macro structures may be uniform or non-uniformthroughout the body of the wicking structure. The macrostructures may bepresent throughout the entire body of the wicking structure,intermittently present throughout the body of the wicking structure,and/or omitted entirely from the body of the wicking structure (e.g.,leaving only sintered powder forming a micro wicking structure). Theabove-described parameters of the macro structures may be tuned to fit asize/shape of an environment in which the tunable wicking structure ispositioned and/or to provide a targeted capillary wicking capability forthe tunable wicking structure and/or for different regions of thetunable wicking structure.

The tunable wicking structures may also include tunable micro wickingstructures having various sinter powder distribution, density, size,sintering characteristics, and/or other parameters. The powder may besintered within electron beam melting (EBM) via a hard sinter parameter,and the parameter set used for manufacturing the micro wickingstructures may be uniform through the body of the wicking structure orvary to provide different structures throughout the body of the wickingstructure. The powder may be sintered via post build heat treatment(e.g., performed after manufacturing the body of the wicking structure).The powder may be light sintered using EBM and encapsulated via a macrostructure, a secondary wick (e.g., formed of ceramic, metal, plastic,and/or other materials) joined to an additive structure associated withthe powder, a membrane, and/or a secondary additive melt operation(e.g., targeting an external region of the micro wickingstructure/external facing powder particles of the wicking structureand/or additional material that is fully melted around the externalregion of the micro wicking structure). For example, a membrane may bejoined with or used to encapsulate the micro wicking structure to allowfor selective filtering/wicking of certain fluids (e.g., using reverseosmosis membranes and/or semipermeable membranes).

The tunable wicking structures described herein enable graded orvariable capillary pumping along a direction, which can achieve improvedpumping action from a bottom of a sump, where the wicking structure mayprovide a higher capillary wicking capability (e.g., via smallerchannels or other parameter adjustments relative to other regions of thewicking structure) in regions where a liquid level is relatively low.Similarly, the wicking structure may be configured to promote uniformradial flow by tuning capillary wicking capability in a radialdirection. Tunable geometry in the wicking structures also enables forpumping over larger distances (e.g., by varying the capillary wickingcapability along a length of the wicking structure). The use of additivemanufacturing to build the wicking structure (e.g., as described withrespect to FIG. 10 ) allows for a continuous change in porosity along adirection of the wicking structure, thereby increasing manufacturingefficiency relative to structures constructed using multi-step sinteringand part joining and providing opportunities for constructing complexwicking structure configurations that are not able to be manufacturedusing other mechanisms.

FIG. 1 schematically shows an exemplary embodiment of an environment fora tunable wicking structure according to the present disclosure: apatient gas delivery system 100 in the form of an anesthesia machine102. Anesthesia machine may include a gas passage 104. Gas passage 104may receive fresh gas from a gas source. Fresh gas in the anesthesiamachine may split into bypass gas and carrier gas, where the bypass gasflows along gas passage 104 to an outlet of the anesthesia machine. Thecarrier gas flows into inflow passage 106 and outflow passage 108, whereit rejoins with the bypass gas, where the bypass gas and carrier gas areultimately supplied to a patient (e.g., via a ventilator mechanism 109).The carrier gas may pick up vaporized anesthetic agent in a vaporreservoir 110. In this way, the gas supplied to the patient may be a mixof bypass gas and carrier gas that includes vaporized anesthetic agent.

Vapor reservoir 110 may be configured to house vaporized anestheticagent received via a port 112 of the vapor reservoir. Port 112 maycouple to a liquid anesthetic agent vaporizer unit 114 via a couplingend 116 of the vaporizer unit 114. The vaporizer unit 114 includes aliquid reservoir 118 that stores liquid anesthetic agent (e.g.,desflurane, isoflurane, sevoflurane, etc.). The anesthetic agent may bepumped into the liquid reservoir 118 via pump 119 (e.g., which may becoupled to a supply of the liquid anesthetic agent, such as aremovable/refillable tank of anesthetic agent that is inserted into theanesthesia machine). An interior of the liquid reservoir may include afirst region 118 a that is fluidically coupled to a second region 118 bvia a passageway 118 c. In some examples, the first region 118 a mayinclude a port or other access region to allow liquid anesthetic agentto be added to the reservoir. The second region 118 b includes a tunablewick 120 that is configured to pull liquid from the reservoir upwardtoward the port 112 (e.g., via capillary action). In some examples, thesecond region 118 b may be sized based on a diameter or width of thetunable wick (e.g., having a diameter and/or width that is less than 5%larger than the diameter and/or width of the wick), and may be smallerin diameter and/or width relative to the first region 118 a.

The vaporizer may include and/or be coupled to a heating element shownschematically at 122. Although positioned externally to a top of thesecond region 118 b of the reservoir, it is to be understood that theheating element 122 may be in any suitable location for heating liquidpulled up by the tunable wick 120 in order to produce vaporizedanesthetic agent to vapor reservoir 110. For example, the heatingelement 122 may additionally or alternatively be positioned in and/oraround port 112, coupled directly to tunable wick 120, and/or otherwisepositioned to vaporize liquid pulled up by tunable wick 120. Thevaporizer and/or heating element 122 may be supplied power fromanesthesia machine via an electrical connection between a firstelectrical connector 124 of the anesthesia machine and a secondelectrical connector 126 of vaporizer unit 114. The power supply to thevaporizer may be modulated via a controller 128 of the anesthesiamachine. The controller 128 may control a heating supplied by theheating element 122, which may in turn control an amount of vaporizationof the anesthetic agent in order to adjust dosage of the anestheticagent. The controller 128 may further control operation of the pump 119in order to adjust an amount of liquid anesthetic agent stored in thereservoir 118.

FIG. 2 shows an exemplary embodiment of a tunable wicking structure 200useable to provide wicking capability through capillary action. In oneembodiment, tunable wicking structure 200 may be used as tunable wick120 of FIG. 1 . Tunable wicking structure 200 includes a macro latticestructure 202, which forms a three-dimensional (3D) grid or matrix ofparallel and/or intersecting lines of material. The spacing between thelines of material forms a plurality of pores 204 that create a macrowicking structure (e.g., where the pores serve as pathways for drawingliquid via capillary action). The material of the macro lattice may beuniform in size, shape, spacing, and/or distribution throughout theentire structure or may be nonuniform in size, shape, spacing, and/ordistribution throughout the entire structure. As used herein, the term“grid” or “matrix” may be understood to include a structure of solidlines of material that are uniform or non-uniform in size, uniform ornonuniform in shape, uniform or non-uniform in spacing, and/or uniformor non-uniform in distribution throughout the structure.

In some examples, the lines of material forming the grid of the latticestructure may be equally spaced, thereby providing a uniform macrostructure of pores. In other examples, the lines of material forming thegrid of the lattice structure may be non-equally spaced, therebyproviding a non-uniform macro structure of pores (e.g., which may betuned for an environment in which the wicking structure is used and atargeted capillary action for different regions of the wicking structurebased on the environment).

The pores 204 are filled with sintered powder (represented by the dottedpattern within the pores 204) to form a micro pore wicking structurewithin the macro lattice structure (e.g., where the spacing betweensurfaces of the powder particles in the pores serve as micro pathwaysfor drawing liquid via capillary action). In this way, the tunablewicking structure 200 provides a two-phase structure using solid andsemi-solid powder. The tunable wicking structure 200 may be formed usingadditive manufacturing, such as electron beam melting (EBM). Forexample, the lattice structure may be formed by completely meltingpowder particles to form the lines of material of the lattice, whereasthe micro pore wicking structure may be formed by only partiallymelting/sintering powder particles, such that only a portion of thesurface of a given powder particle is joined to a surface of an adjacentpowder particle, creating a space between regions of the joined powderparticles.

The use of additive manufacturing to form a wicking structure allows forflexible tuning of different parameters of the structure. For example,parameters such as part strength, thermal properties, mass, density, anddamping characteristics, among other parameters, may be tuned vialattice size, shape, and/or orientation. The wicking structure may befurther tuned via sinter powder distribution. For example, sinter powdermay be distributed uniformly throughout each pore of the latticestructure, or non-uniformly (e.g., providing smaller capillaries incertain regions of the wicking structure relative to other regions). Insome examples, a porosity of the wicking structure (e.g., a size of thepores of the lattice structure and/or a size of channels formed betweenpowder particles of the micro pore wicking structure) may becontinuously variable along at least one dimension of the wickingstructure (e.g., along a length of the wicking structure, around acircumference of the wicking structure, etc.) and may be achieved in oneor more ways including variable sintering parameters within or outsideof the additive manufacturing process.

FIG. 3 shows another exemplary embodiment of a tunable wicking structure300. Tunable wicking structure 300 may be similar to wicking structure200 of FIG. 2 , and may include a macro lattice structure 302 (analogousto macro lattice structure 202 of FIG. 2 ) that forms pores 304(analogous to pores 204 of FIG. 2 ) that are filled with sintered powder(represented by the dotted pattern within the pores 304). Tunablewicking structure 300 may further be at least partially encapsulated byencapsulation structure 306. In the illustrated example, encapsulationstructure 306 comprises a solid structure enclosing and encircling acircumference of the overall cylindrical macro lattice structure 302.The encapsulation structure 306 may be formed of the same material ormaterial composition as the macro lattice structure 302 and/or thepowder filling pores of the lattice structure in some examples. In otherexamples, the encapsulation structure 306 may be formed of a differentmaterial or material composition from the macro lattice structure 302and/or the powder filling pores of the lattice structure. The materialused for the encapsulation structure 306 may depend on an environment ofthe tunable wicking structure 300 (e.g., having heat transferproperties, durability properties, elastomeric properties, weightproperties, and/or other parameters selected for the environment and/oruse of the wicking structure).

FIG. 4 shows a cross-sectional view of an exemplary embodiment of atunable wicking structure 400. For example, tunable wicking structure400 may be shown as a cross-sectional view of a portion of tunablewicking structure 300 of FIG. 3 . Tunable wicking structure 400 includesa lattice structure 402 forming pores 404 that are filled with powder asdescribed above with respect to lattice structure 302 and pores 304 ofFIG. 3 . An encapsulation structure 406 is provided around the latticestructure 402 and may be analogous to encapsulation structure 306 ofFIG. 3 .

As described above, various parameters of a wicking structure accordingto the present disclosure may be tuned for different usage environments.An example alternative configuration of a tunable wicking structure isshown in FIG. 5 . In contrast to the tunable wicking structure of FIG. 4, which illustrates an exemplary embodiment having lattice structurecomponents extending the entire length/height of the wicking structureand the entire width between interior surfaces of the encapsulationstructure. FIG. 5 illustrates an exemplary embodiment of a tunablewicking structure 500 which includes different sub-structures indifferent sections of the wicking structure. For example, tunablewicking structure 500 includes a first lattice structure 502 in a topregion of the wicking structure. The first lattice structure 502 may beanalogous to the lattice structure 402 of FIG. 4 and/or the latticestructure 302 of FIG. 3 and may form a macro wicking structure havingpores that are filled with powder to create a micro wicking structure asdescribed above. The first lattice structure 502 forms an uppermostand/or top surface of the wicking structure and extends downward fromthe uppermost and/or top surface along a height of the wicking structuretoward a lowermost and/or bottom surface of the wicking structure. Inthe illustrated example, the first lattice structure 502 has a heightthat is less than a third of the overall height of the tunable wickingstructure 500 (e.g., the first lattice structure 502 may have a heightthat is in a range of 10-15% of the overall height of the tunablewicking structure 500).

A second lattice structure 504 is positioned in a bottom region of thetunable wicking structure 500. The description of the configuration ofthe first lattice structure 502 may also apply to the second latticestructure 504. The second lattice structure 504 forms the lowermostand/or bottom surface of the tunable wicking structure and extendsupward from the lowermost and/or bottom surface along the height of thewicking structure toward the uppermost and/or top surface of the wickingstructure. In the illustrated example, the second lattice structure 504has a height that is less than a third of the overall height of thetunable wicking structure 500 (e.g., the second lattice structure 504may have a height that is in a range of 10-15% of the overall height ofthe wicking structure 500). In some examples, the configuration of thefirst lattice structure 502 may be substantially the same as theconfiguration of the second lattice structure 504. For example,dimensions of the first and second lattice structures (e.g., overallheight, overall width/diameter, pore size/lattice spacing, thickness ofthe lines of material forming the grid pattern of the lattice, etc.),composition of the first and second lattice structures (e.g.,material(s) used to form the lattice structures), powder particledistribution/density/size within pores of the lattice, and/or otherparameters of the first and second lattice structures may besubstantially the same as one another. In other examples, one or more(or all) of the above-described parameters may be different in the firstlattice structure relative to the second lattice structure.

An open powder region 506 is sandwiched between the first and secondlattice structures of the wicking structure 500. The open powder regionmay include only powder particles forming a micro wicking structure anddoes not include a macro lattice structure. In some examples, the openpowder region 506 may be formed similarly to the first and secondlattice structures, with an additional process of removing the latticestructure such that only the powder particles disposed in the pores ofthe (removed) lattice structure are present in the open powder region.In the illustrated example, the open powder region 506 extends between abottom surface of the first lattice structure 502 and a top surface ofthe second lattice structure 504. The open powder region 506 may extendalong more than a third of the overall height of the wicking structure500 (e.g., the open powder region 506 may have a height that is in arange of 70-80% of the overall height of the wicking structure 500). Insome examples, the open powder region 506 may have substantially thesame powder particle density, distribution, and/or size/size variationas the powder within the pores of the first lattice structure 502 and/orthe second lattice structure 504. In other examples, the open powderregion 506 may include a different powder particle density,distribution, and/or size/size variations as the powder within the poresof the first lattice structure 502 and/or the second lattice structure504. The open powder region 506 may be uniform throughout the entireregion (e.g., having substantially the same powder particle density,distribution, and/or size/size variation) in some examples. In otherexamples, the open powder region 506 may have a non-uniform and/orgraduated powder particle density, distribution, and/or size/sizevariation throughout the region. In an illustrative example, powderparticle density may be less dense (e.g., having larger channels betweenpowder particles) in a first portion of the open powder region toward atop of the region and may (e.g., linearly or non-linearly) increase indensity in a second portion of the open powder region toward a bottom ofthe region.

An encapsulation structure 508 is provided around the first latticestructure 502, the second lattice structure 504, and the open powderregion 506. The encapsulation structure 508 may be analogous toencapsulation structure 306 of FIG. 3 and/or the encapsulation structure406 of FIG. 4 . An inner surface of the encapsulation structure 508 maybe adjacent to and/or in direct contact with each of the first latticestructure 502, the second lattice structure 504, and the open powderregion 506. In this way, a width/diameter of each of the first latticestructure 502, the second lattice structure 504, and the open powderregion 506 may be defined as extending the width/diameter of an interiorregion within the encapsulation structure 508 (e.g., with a perimeter ofthe interior region of the encapsulation structure 508 formed by aninterior surface(s) of the encapsulation structure 508). For example,the plurality of powder particles in the open powder region 506 oftunable wicking structure 500 may include a first subset of powderparticles and a second subset of powder particles, each powder particleof the first set of powder particles being only partially joined to therespective at least one other powder particle of the micro wickingelement and not joined to any other structure, and each powder particleof the second set of powder particles being further partially joined tothe encapsulation structure.

The exemplary embodiment of FIG. 5 shows a mixed use of powder particlesencased in a macro lattice structure (e.g., first and second latticestructures 502 and 504) and powder particles not encased in a macrolattice structure (e.g., open powder region 506). It is to be understoodthat other examples of wicking structures may include only an openpowder region with no lattice structure (e.g., where the powderparticles of the wicking structure are only partially joined to one ormore adjacent powder particles and are not joined to any otherstructural element such as a macro lattice structure). Latticestructures may provide additional durability and contactable surfacearea relative to open powder regions. Removing the lattice structure(e.g., having a wicking structure that does not include a latticestructure and only includes open powder regions) may increase overallcapillary wicking capabilities (e.g., capillary wicking strength and/orcapacity). Accordingly, wicking structures utilizing lattice structuresmay be selected for usage environments in which the added durability ofthe lattice structures and/or the added surface area of the latticestructures (e.g., for providing heat transfer, such as in embodimentswhere the wicking structure is directly coupled to a heating element) isuseful. Wicking structures utilizing only open powder regions (e.g.,with no lattice structure) may be selected for usage environments inwhich improved capillary action is useful.

FIGS. 6A-C and 7A-C show detailed, microscopic views of exemplaryembodiments of tunable wicking structures, such as the tunable wickingstructures 200 and 300 of FIGS. 2 and 3 , respectively. FIGS. 6A-C showmicroscopic views of a tunable wicking structure in which a lattice ismaintained for the wicking structure, with powder particles disposed invoids of the lattice to provide micro pores for micro capillary action(e.g., where the voids of the lattice provide macro pores for macrocapillary action). For example, the tunable wicking structureillustrated in FIGS. 6A-C may be an example of the powder particles andlattice structure in the tunable wicking structure 400 of FIG. 4 and/orthe first lattice structure 502 and/or second lattice structure 504 ofthe tunable wicking structure 500 of FIG. 5 . In FIG. 6A, an exemplary100× magnification of a portion of a tunable wicking structure 600 isshown, with solid regions of the lattice shown at 602 and powderparticles shown at 604. FIG. 6B shows an exemplary 250× magnification ofthe portion of the tunable wicking structure 600 and FIG. 6C shows anexemplary 1000× magnification of the portion of the tunable wickingstructure 600. As most clearly visible in FIG. 6C, the powder particlesexhibit necking (e.g., partial bonding with adjacent particles)indicating sintering of the particles.

FIGS. 7A-C shows a microscopic view of a tunable wicking structure inwhich a lattice is removed or not printed for the tunable wickingstructure (e.g., wherein the tunable wicking structure is formed of openpowder with no macro structure for holding the powder). For example, thetunable wicking structure illustrated in FIGS. 7A-C may be an example ofthe powder particles in the open powder region 506 of tunable wickingstructure 500 of FIG. 5 . In FIG. 7A, an exemplary 100× magnification ofa portion of a tunable wicking structure 700 is shown, with powderparticles shown at 702. FIG. 7B shows an exemplary 250× magnification ofthe portion of the tunable wicking structure 700 and FIG. 7C shows anexemplary 1000× magnification of the portion of the tunable wickingstructure 700. As most clearly visible in view FIG. 7C, the powderparticles exhibit necking (e.g., partial bonding with adjacentparticles) indicating sintering of the particles. In each of theexemplary embodiments of FIGS. 6A-C and 7A-C, the tunable wickingstructures exhibit no powder fallout during cutting, as the necking ofthe powder particles serves to strengthen the overall structure whilestill allowing for the passage of liquid in gaps between the powderparticles.

FIGS. 8 and 9 show exemplary embodiments of environments in whichtunable wicking structures (e.g., corresponding to tunable wickingstructure 200 of FIG. 2 , tunable wicking structure 300 of FIG. 3 and/orany of the above-described tunable wicking structures) may beincorporated. FIG. 8 shows a cross-section of a heat pipe 800 in whichliquid may be drawn downward via capillary action in a tunable wickingstructure 802. A heating element 804 may be positioned at the bottom ofthe heat pipe and/or around a bottom periphery of the tunable wickingstructure 802 in order to heat the liquid drawn by the wicking structureuntil the liquid is vaporized. Vaporized liquid may flow upward througha vapor chamber 806 of the heat pipe. In the example of FIG. 8 , thewicking structure may have a non-uniform composition, in which poresizes, powder particle sizes, powder sintering amount, powder density,and/or other parameters of the wicking structure may be different indifferent regions of the same wicking structure. For example, pore sizesmay be larger and/or powder density may be denser in a top region of thetunable wicking structure relative to a bottom region of the tunablewicking structure.

FIG. 9 shows a cross-section of a portion of an air/liquid separator900. An air/liquid mix may enter an opening 902 of a channel 904. Atunable wicking structure 906 may be positioned within the channel 904(e.g., along a side wall of the channel), extending a portion of thelength of the channel. The tunable wicking structure 906 may beconfigured to extract liquid from the air/liquid mix, drawing the liquidtoward a liquid outlet 908 and allowing air to pass through the channel904 toward an air outlet 910. In this way, the liquid from theair/liquid mix may be directed to a different component than the airfrom the air/liquid mix. The tunable wicking structure 906 may form anair barrier, keeping air moving in the channel 904 while pulling outliquid to a different receptacle. In the example of FIG. 9 , the tunablewicking structure may have a non-uniform composition, in which poresizes, powder particle sizes, powder sintering amount (e.g., amount ofmelting/joining of powder particles), powder density, and/or otherparameters of the wicking structure may be different in differentregions. For example, pore sizes may be larger and/or powder density maybe denser in a top region of the wicking structure relative to a bottomregion of the wicking structure in order to increase capillary actiontoward the liquid outlet. The wicking structure 906 of FIG. 9 may alsobenefit from a non-uniform size/shape that complements the shape ofchannel 904. Such non-uniformity may be achieved using a manufacturingmethod such as an additive manufacturing method, an example of which isdescribed with respect to FIG. 10 .

It is to be understood that the tunable wicking structures describedherein may be used in other environments without departing from thescope of this disclosure. In another example, a wicking structure mayform a tree-like structure, in which a source of liquid may be pulledfrom a “trunk” of the tree-like structure and distributed out to manyother liquid sources and/or sinks via “branches” of the treelikestructure. In this way, the amount of liquid drawn to the varioussources and/or sinks may be controlled by providing different geometriesand/or other wicking properties of each “branch” of the tree-likestructure.

For example, each “branch” of the tree-like structure may include awicking structure that is tuned for a particular speed, acceleration,amount, and/or other parameter of liquid delivery based on anenvironment in which that “branch” is located and/or a source/sink towhich that “branch” is delivering the liquid. In this way, one or more“branches” may form wicking structures that are tuned to deliver liquidat a faster speed, a faster acceleration, and/or a greater amount thananother “branch.” In some examples, a first “branch” may include awicking structure tuned to deliver liquid at a faster speed than asecond “branch,” while the second “branch” may include a wickingstructure tuned to deliver a greater amount of liquid at a given timerelative to the first “branch.” Any of the above-described parameters ofthe wicking structures in the tree-like structure may be tuned (e.g.,pore size, wicking structure geometry, powder particle density, etc.) inorder to provide a capillary wicking capability that is tuned for anassociated environment of each “branch” of the tree-like structure.

The above-described tree-like structure may be used for any of the abovedescribed tunable wicking structures. For example, the patient gasdelivery system 100 of FIG. 1 may incorporate a tunable wickingstructure having the above-described tree-like structure in order todeliver liquid anesthetic agent to multiple regions at different speeds,accelerations, in different amounts, etc. as described above.

FIG. 10 is a flow chart illustrating an exemplary embodiment of a method1000 for manufacturing a wicking structure (e.g., wicking structure 200of FIG. 2 and/or wicking structure 300 of FIG. 3 ). Method 1000 may becarried out at least in part by additive manufacturing, as performed bythree-dimensional (3D) printing device, which may beoperatively/communicatively coupled to a printer-interfacing computingdevice.

At 1002 a 3D model of the wicking structure is obtained and/orgenerated. The model of the wicking structure may be a computer aideddesign (CAD) file, additive manufacturing file (AMF), or other 3Dmodeling file. The 3D model of the wicking structure may be generated onthe printer-interfacing computing device. In some examples, the 3D modelmay be generated entirely from operator instructions via the CAD orother program. In other embodiments, the 3D model may be generated atleast in part from information received from a 3D scanner (e.g., a laserscanner) that may image a physical model of the wicking structure. The3D model may define the dimensions of the wicking structure (e.g., alattice defining the wicking structure), exterior and interiorstructures of the wicking structure (e.g., the lattice, a configurationof interior powder filling pores of the lattice, any exteriorencapsulating structure, etc.), and material properties of the wickingstructure, thereby fully representing, in a digital format, the finalform of the wicking structure that will be produced. As appreciated byFIGS. 2 and 3 , the wicking structure includes voids (e.g., empty space)and thus the 3D model of the wicking structure may include supportstructures, fill material, and/or other features that allow for printingover the voids. The 3D model may include a base portion of the wickingstructure (e.g., from which the wicking structure extends) in order toproduce a wicking structure that includes the base portion integratedwith the meshwork of the wicking structure. In other embodiments, thebase portion may be manufactured separately from the meshwork of thewicking structure, and thus may not be included in the 3D model. In someexamples, the wicking structure may also be created entirely from theadditive manufacturing machine parameters and not specifically definedin the model geometry. For example, the wick may be represented by asimplified solid cylinder 3D model and formed as a porous wick bydefining the appropriate additive manufacturing machine parameters toyield a sintered or semi-sintered structure as previously described.

At 1004, a plurality of two-dimensional (2D) slices of the 3D model ofthe wicking structure are generated. The slices may be generated on theprinter interfacing computing device and then the plurality of slicesare sent to the printing device as an STL file, or the 3D model of thewicking structure may be sent to the printing device, and the printingdevice may slice the 3D model into the plurality of slices to generatean STL file. In doing so, the 3D model is sliced into hundreds orthousands of horizontal layers of a suitable thickness, such as athickness in a range from 0.01 mm to 3 mm.

At 1006, the printing device prints the first slice on a build plate orother suitable base material. When the printing device prints from theSTL file, the printing device creates or prints the wicking structurelayer-by-layer on the build plate. The printing device reads every slice(or 2D image) from the 3D model and proceeds to create the 3D wickingstructure by laying down (or printing) successive layers of material onan upper, planar surface of the build plate until the entire wickingstructure is created. Each of these layers can be seen as a thinlysliced horizontal cross section of the eventually completed or printed3D wicking structure.

The printing device may be a suitable device configured to print metaland/or other high magnetic permeability materials, such as aluminum orstainless steel. The printing device may utilize electron beam melting(EBM) technology, selective laser melting (SLM) technology, direct metallaser sintering (DMLS) technology, or other suitable metal printingtechnology. In some examples, the printing device may be configured toprint multiple materials (e.g., the lattice and the fill powdermaterial, or different portions of the lattice and/or fill powdermaterial) and thus may include more than one print head.

During printing, the print head(s) is moved, in horizontal and/orvertical directions, to complete or print each layer of the 3D model, bya controlled mechanism that is operated by control software running onthe printing device, e.g., a computer-aided manufacturing (CAM) softwarepackage adapted for use with the printing device. The build plate may bethe component that is moved in the Z direction while the print head orlasers/electron beams may be moved in the X-Y directions to create thelayers. The printed material solidifies to form a layer (and to sealtogether layers of the 3D wicking structure), and the print head orbuild plate is then moved vertically prior to starting the printing ofthe next layer. This process is repeated until all layers of the 3Dwicking structure have been printed.

Accordingly, at 1008, each additional slice is sequentially printed. Inexemplary embodiments where EBM technology is used to print the wickingstructure, a sequential operation may include spreading a thin layer ofpowder (e.g., metal, such as titanium, or another material) on top ofthe build plate. In a next step of the sequential operation, an electronbeam may be used to do an initial light sinter (e.g., using a first,weak electron beam or other heating mechanism) of the entire build platein order to cause particles of the powder to lightly stick together andcounteract repelling forces that are created due to charge build-up inthe powder during later electron beam bombardment of the powder. Thelight sintering may create a powder cake. After the light sintering, astronger, more powerful electron beam (relative to the electron beam orother heating mechanism used for the light sintering) may be used tomelt each slice of the wicking structure. For each slice of the wickingstructure, one or more steps of the following process may repeat:spreading a thin layer of powder on top of a last printed layer of thewicking structure, performing a light sintering of the powder (e.g., allof the thinly-spread powder), and directing an electron beam to melt arespective layer of the wicking structure. For example, the electronbeam may be targeted to areas in a location of a line of a latticestructure of the wicking structure and/or areas in a location of anencapsulation structure of the wicking structure for a given slice ofthe wicking structure.

At 1010, the printed wicking structure is dried, cured, and/or heattreated (e.g., different heat-related processes may be performed basedon a type of additive manufacturing used to build the structure). Thedrying/curing/heat treatment of the printed wicking structure may beperformed after each layer deposition, and/or the drying/curing/heattreatment may be performed after the entire wicking structure isprinted. In some examples, the drying/curing/heat treatment may includea postprocess/post-build heat treatment, where the entire wickingstructure, including the powder within voids in the lattice, is heatedright up to a melting point of the powder and/or just below the meltingpoint of the powder in order to cause adjacent powder particles toexhibit necking, as shown in FIGS. 6 and 7 . At 1012, any excessmaterial (e.g., that did not bond with any adjacent powder particlesduring the post-process heat treatment) may optionally be removed. Forexample, the wicking structure may be placed into water, acid, or othersolvent to at least partially dissolve the access material and/or thewicking structure may be subjected to external forces such as airblasting, vibration, etc. in order to separate excess material from thewicking structure. In another example, if support structures are printedin the voids (e.g., scaffolding-like structures or perforatedstructures), the support structures may be removed manually and/or witha tool.

Thus, method 1000 provides for 3D printing of a wicking structure. Whilemethod 1000 is directed to printing the entire wicking as a singlecomponent, in some examples, the 3D model of the wicking structure mayinclude multiple 3D models, each of a different section of the wickingstructure. For example, the wicking structure may be divided into aplurality of sections, such as a first section that includes the baseportion and a first set of lines of material (e.g., lines of materialthat are intersecting, parallel, and/or otherwise positioned), a secondsection that includes a second set of (e.g., intersecting, parallel,etc.) lines of material, a third section that includes a third set of(e.g., intersecting, parallel, etc.) lines of material, and so forth.Each section may be printed independently, and then the sections may bestacked and fused together using a suitable mechanism. In such examples,void structures may be reduced or eliminated, which may lower the costof manufacture.

In still further examples, the wicking structure may be manufacturedusing a mold. The mold may be generated by first 3D printing a model ofthe wicking structure in a suitable material that may be solid at roomtemperature but changes to liquid at a relatively low temperature thatis greater than room temperature, such as wax. A plaster mold may beformed over the wax model, and after the plaster dries, the wax may bemelted and drained from the mold. The mold may then be filled withmolten metal. Once the metal cools, the plaster may be removed togenerate the wicking structure.

Thus, the wicking structure described above with respect to FIGS. 1-9may be manufactured using additive manufacturing technology, such as 3Dprinting. In an exemplary embodiment, the wicking structure describedherein may be manufactured according to a computer readable mediumcontaining computer readable instructions which, when executed on a 3Dprinter, cause the printer to print the wicking structure, where thewicking structure comprises a macro wicking element including a latticestructure formed by a grid of intersecting lines of material, thelattice structure including pores formed between the (e.g.,intersecting, parallel, etc.) lines of material, and a micro wickingelement including powder particles distributed within the pores of thelattice structure. In some examples, all or a portion of the latticestructure may be removed after printing, leaving just the powderparticles forming the micro wicking structure.

In an example, a method of creating a computer readable 3D modelsuitable for use in additive manufacturing of a wicking structure, whichmay be configured to be housed in a vaporizing chamber of an anestheticagent delivery system in some examples, is provided, wherein the wickingstructure comprises a macro wicking element including a latticestructure formed by a grid or matrix of (e.g., intersecting, parallel,etc.) lines of solid material (e.g., uniform or random in size, shape,spacing, or distribution), the lattice structure including pores formedbetween the lines of material, and a micro wicking element includingpowder particles distributed within the pores of the lattice structure.In some examples the wicking structure may further include anencapsulation structure disposed around an outer surface of the macrowicking element. In some examples, the lattice structure may beconfigured to be removed, such that the wicking structure in a finalizedform only includes the powder particles of the micro wicking element. Inan example, the method includes obtaining specifications of the wickingstructure. The specifications may be obtained from user input (e.g., viaa 3D modeling program such as CAD) and/or from information obtained froma 3D scanner. For example, the 3D scanner may image a physical model orprototype of the wicking structure. The method further includesgenerating the computer readable 3D model of the wicking structure basedon the obtained specifications. The 3D model may be generated using CADor another 3D modeling program. In some examples, the method furtherincludes sending the 3D model to a printing device. The 3D model may beconverted into an STL file or other suitable format readable by theprinting device. The printing device may then print the wickingstructure according to the specifications set forth by the 3D model. Thewicking structure may be wicking structure 200 of FIG. 2 and/or wickingstructure 300 of FIG. 3 , or any of the other wicking structuresdisclosed herein, for example.

The formation of the wicking structure in layers may also allow thewicking structure to be readily varied, with regards to geometry andconfiguration of powder particles and lattice structure. For example, asthe layers of the wicking structure are formed, the material forms anopen cell structure. A geometry of each cell of the open cell structuremay be shaped by the alignment of the layers. If the layers are exactlyaligned, each cell may have a same shape. In other examples, thestaggering of layers may result in irregular, variable cell geometries.

A technical effect of a wicking structure formed of a plurality ofpowder particles is that a capillary action of the wicking structure istunable via variation of properties of the powder particles and anyassociated structural components (e.g., a lattice macro structure, anencapsulating structure, etc.).

FIGS. 2-7 show example configurations with relative positioning of thevarious components. If shown directly contacting each other, or directlycoupled, then such elements may be referred to as directly contacting ordirectly coupled, respectively, at least in one example. Similarly,elements shown contiguous or adjacent to one another may be contiguousor adjacent to each other, respectively, at least in one example. As anexample, components laying in face-sharing contact with each other maybe referred to as in face-sharing contact. As another example, elementspositioned apart from each other with only a space there-between and noother components may be referred to as such, in at least one example. Asyet another example, elements shown above/below one another, at oppositesides to one another, or to the left/right of one another may bereferred to as such, relative to one another. Further, as shown in thefigures, a topmost element or point of element may be referred to as a“top” of the component and a bottommost element or point of the elementmay be referred to as a “bottom” of the component, in at least oneexample. As used herein, top/bottom, upper/lower, above/below, may berelative to a vertical axis of the figures and used to describepositioning of elements of the figures relative to one another. As such,elements shown above other elements are positioned vertically above theother elements, in one example. As yet another example, shapes of theelements depicted within the figures may be referred to as having thoseshapes (e.g., such as being circular, straight, planar, curved, rounded,chamfered, angled, or the like). Further, elements shown intersectingone another may be referred to as intersecting elements or intersectingone another, in at least one example. Further still, an element shownwithin another element or shown outside of another element may bereferred as such, in one example.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralof said elements or steps, unless such exclusion is explicitly stated.Furthermore, references to “one embodiment” of the present invention arenot intended to be interpreted as excluding the existence of additionalembodiments that also incorporate the recited features. Moreover, unlessexplicitly stated to the contrary, embodiments “comprising,”“including,” or “having” an element or a plurality of elements having aparticular property may include additional such elements not having thatproperty. The terms “including” and “in which” are used as theplain-language equivalents of the respective terms “comprising” and“wherein.” Moreover, the terms “first,” “second,” and “third,” etc. areused merely as labels, and are not intended to impose numericalrequirements or a particular positional order on their objects.

This written description uses examples to disclose the invention,including the best mode, and also to enable a person of ordinary skillin the relevant art to practice the invention, including making andusing any devices or systems and performing any incorporated methods.The patentable scope of the invention is defined by the claims, and mayinclude other examples that occur to those of ordinary skill in the art.Such other examples are intended to be within the scope of the claims ifthey have structural elements that do not differ from the literallanguage of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal languages ofthe claims.

What is claimed is:
 1. A method for creating a wicking structure,comprising: creating, using a 3D printing technique, a macro wickingelement comprising a lattice structure formed by a grid of a firstmaterial, the lattice structure comprising pores formed between the gridof first material; creating, using the 3D printing technique, a firstmicro wicking element comprising powder particles distributed within thepores of the lattice structure; and creating, using the 3D printingtechnique, a second micro wicking element by removing at least a portionof the lattice structure.
 2. The method for creating the wickingstructure of claim 1, wherein the grid of the first material comprises aset of parallel lines and a set of intersecting lines.
 3. The method forcreating the wicking structure of claim 1, wherein the first microwicking element and the second micro wicking element are created basedon a physical model obtained from a 3D scanner.
 4. The method forcreating the wicking structure of claim 1, wherein the first microwicking element and the second micro wicking element are created basedon one or more specifications obtained from a 3D modeling program. 5.The method for creating the wicking structure of claim 1, wherein eachpowder particle of the first micro wicking element is partially joinedto at least one other powder particle of the wicking structure, andwherein a plurality of channels are formed between partially joinedpowder particles of the first micro wicking element for drawing liquidthrough the wicking structure via capillary action, the wickingstructure having one or more tunable parameters to adjust capillaryaction capabilities of the wicking structure.
 6. The method for creatingthe wicking structure of claim 1, further comprising an encapsulationstructure disposed around an outer surface of the macro wicking element.7. The method for creating the wicking structure of claim 1, wherein aporosity of the wicking structure is continuously variable along atleast one dimension of the wicking structure.
 8. The method for creatingthe wicking structure of claim 1, wherein the grid of the first materialforming the lattice structure has a same material composition as thepowder particles distributed within the pores of the lattice structureand wherein a size, shape, spacing, and/or distribution of the firstmaterial is uniform throughout the lattice structure.
 9. The method forcreating the wicking structure of claim 1, wherein the wicking structureis a wick of a vaporizer of an anesthesia machine.
 10. The method forcreating the wicking structure of claim 1, wherein the powder particlesof the first micro wicking element are distributed uniformly throughoutthe pores of the lattice structure.
 11. The method for creating thewicking structure of claim 1, wherein the powder particles of the firstmicro wicking element are distributed non-uniformly throughout the poresof the lattice structure.